Electronic device

ABSTRACT

According to the present invention, air conduction sound and human body vibration sound (e.g. bone conduction sound) are transmitted to a user without a need for pressing a vibration body itself to an ear. An electronic device  1  of the present invention includes: a panel  10 ; a housing  60  configured to support the panel  10 ; and a piezoelectric element  30  attached to the panel  10 . The panel  10  is deformed due to deformation of the piezoelectric element  30 , and air conduction sound and human body vibration sound are transmitted to an object that is in contact with the deformed panel  10.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Japanese PatentApplication No. 2012-75124 filed on Mar. 28, 2012, the entire contentsof which are incorporated herein by reference.

FIELD

The present invention relates to an electronic device that vibrates apanel by applying a predetermined electric signal (i.e. a sound signal)to a piezoelectric element and that transfers the vibration of the panelto a human body to thereby transmit air conduction sound and human bodyvibration sound to a user.

BACKGROUND

Patent Literature 1 listed below describes an electronic device such asa mobile phone that transmits air conduction sound and bone conductionsound to a user. Patent Literature 1 also describes that the airconduction sound is sound perceived by an auditory nerve of a user as aresult of an eardrum being vibrated by an air vibration that is createdby a vibration of an object and that travels through an externalauditory canal down to the eardrum. Furthermore, Patent Literature 1describes that human body conduction sound is transmitted to theauditory nerve of the user through a part of a user's body (e.g. acartilaginous portion of an external ear) that is in contact with thevibrating object.

According to Patent Literature 1, in the described mobile phone, arectangular plate-shaped vibration body configured by piezoelectricbimorph and a flexible material is attached to an outer surface of ahousing via an elastic member. Patent Literature 1 also describes that,upon application of a voltage to the piezoelectric bimorph of thevibration body, the piezoelectric material is expanded and contracted ina longitudinal direction, thereby causing the vibration body to undergoflexture vibration. As a result, when the user places the vibration bodyin contact with an auricle, air conduction sound and human bodyconduction sound are transmitted to the user.

CITATION LIST

Patent Literature 1 Japanese Patent Application Publication No.2005-348193

SUMMARY

In the electronic device described in Patent Literature 1, the vibrationbody is attached to the outer surface of the housing of the mobile phoneor the like. Accordingly, the vibration body projecting from the outersurface of the housing needs to be pressed to an ear, which sometimescauses usability problems.

The present invention is to provide an electronic device that is capableof transmitting air conduction sound and human body vibration sound to auser without the need for pressing the vibration body itself to the ear.

One aspect of the present invention resides in an electronic device thatincludes: a panel; a housing configured to support the panel; and apiezoelectric element attached to a surface of the panel on an innerside of the housing. The panel is deformed due to deformation of thepiezoelectric element, and air conduction sound and human body vibrationsound are transmitted to an object that is in contact with the deformedpanel.

The piezoelectric element may be attached to the surface of the panel onthe inner side of the housing.

A vibration may occur in an area of the panel that is larger than anarea having a length corresponding to a distance from an inferior crusof antihelix to an antitragus and a width corresponding to a distancefrom a tragus to an antihelix of an ear of a human being.

The piezoelectric element may be joined to the panel by a first joiningmember.

The first joining member may be a non-thermosetting adhesive agent.

The first joining member may be a double-sided adhesive tape.

The panel may be joined to the housing by a second joining member.

The second joining member may be a non-thermosetting adhesive agent.

The second joining member may be a double-sided adhesive tape.

The panel may form a part or an entirety of any of a display panel, anoperation panel, a cover panel, and a lid panel that allows arechargeable battery to be detachable.

When the panel is the display panel, the piezoelectric element may bedisposed outside of a display area provided for a display function ofthe display panel.

The deformation, which causes the transmission of air conduction soundand human body vibration sound, may occur in any areas of the panel.

The panel may include, in areas thereof that are vibrated, a pluralityof portions that are configured to be vibrated in a directionintersecting with a surface of the panel, and in each of the pluralityof portions, a value indicating an amplitude of the vibration maytransition over time from plus to minus or vice versa.

According to an electronic device of the present invention, airconduction sound and human body vibration sound are transmitted to theuser without the need for pressing the vibration body itself to the ear.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be further described below with reference tothe accompanying drawings, wherein:

FIG. 1 is a function block diagram of an electronic device according toone embodiment of the present invention;

FIG. 2 illustrates a preferable shape of a panel;

FIGS. 3A and 3B illustrate a housing structure of an electronic deviceaccording to another embodiment;

FIG. 4 illustrates one example of a vibration of a panel of theelectronic device according to the other embodiment;

FIGS. 5A-5C illustrate a housing structure of an electronic deviceaccording to yet another embodiment;

FIG. 6 illustrates one example of a vibration of a panel of theelectronic device according to the yet other embodiment; and

FIG. 7 illustrates one example of joining between a panel and a housing.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described with reference tothe accompanying drawings. FIG. 1 is a function block diagram of anelectronic device 1 according to one embodiment of the presentinvention. The electronic device 1, which is a mobile phone(smartphone), for example, includes a panel 10, a display unit 20, apiezoelectric element 30, an input unit 40, and a control unit 50.

The panel 10 may be a touch panel configured to detect a contact, acover panel configured to protect the display unit 20, or the like. Thepanel 10 may be made of glass or a synthetic resin such as acryl. Thepanel 10 preferably has a plate shape. The panel 10 may be a flat plateor a curved panel having a gradually inclined surface. When the panel 10is the touch panel, the panel 10 detects a contact made by a finger of auser, a pen, a stylus pen, or the like. The touch panel may detect acontact using any type, such as the capacitive type, the resistive filmtype, a surface acoustic wave type (or an ultrasonic type), an infraredtype, an electromagnetic induction type, a load detection type, and thelike.

The display unit 20 is a display device such as a liquid crystaldisplay, an organic EL display, and an inorganic EL display. The displayunit 20 is disposed on a back surface of the panel 10. The display unit20 may be disposed on the back surface of the panel 10 using a joiningmember (e.g. an adhesive agent). The display unit 20 may also be adheredto the panel 10 by the joining member (e.g. the adhesive agent). Asanother example, the display unit 20 may be disposed to be spaced apartfrom the panel 10 and supported by the housing of the electronic device1.

The piezoelectric element 30 is an element that is configured to undergoexpansion and contraction or bending (flexure) in accordance with anelectromechanical coupling factor of a constituent material in responseto an electric signal (voltage) applied thereto. As a material of theelement, ceramic and crystal are used, for example. The piezoelectricelement 30 may be a unimorph, a bimorph, or a laminated piezoelectricelement. The laminated piezoelectric element includes a laminatedunimorph element in which layers (e.g. 16 or 24 layers) of unimorph arelaminated or a laminated bimorph element in which layers (e.g. 16 or 24layers) of bimorph are laminated. The laminated piezoelectric element isconfigured by a laminated structure of a plurality of dielectric layersmade of PZT (lead zirconate titanate) and electrode layers each disposedbetween adjacent ones of the dielectric layers, for example. Unimorphundergoes expansion and contraction in response to an electric signal(voltage) applied thereto, and bimorph undergoes bending in response toan electric signal (voltage) applied thereto.

The piezoelectric element 30 is disposed on the back surface of thepanel 10 (i.e. a surface of an inner side of the electronic device 1).The piezoelectric element 30 is attached to the panel 10 by a joiningmember (e.g. a double-sided adhesive tape). The piezoelectric element 30may be attached to the panel 10 via an intermediate member (e.g. a metalplate). The piezoelectric element 30 is at a predetermined distance froma surface of an inner side of a housing 60 in a state where thepiezoelectric element 30 is disposed on the back surface of the panel10. Preferably, the piezoelectric element 30 remains at a predetermineddistance from the surface of the inner side of the housing 60 even in astate where the piezoelectric element 30 undergoes expansion andcontraction or flexture. That is to say, the distance between thepiezoelectric element 30 and the surface of the inner side of thehousing 60 is preferably greater than a maximum amount of deformation ofthe piezoelectric element 30.

The input unit 40 is configured to receive an operation input from theuser and is configured using an operation button (an operation key), forexample. When the panel 10 is the touch panel, the panel 10 is alsocapable of receiving an operation input from the user by detecting acontact made by the user.

The control unit 50 is a processor configured to control the electronicdevice 1. The control unit 50 applies, to the piezoelectric element 30,a predetermined electric signal (voltage corresponding to a soundsignal). The voltage that the control unit 50 applies to thepiezoelectric element 30 may be ±15 V which is greater than ±5 V, thatis, a voltage to be applied to a so-called panel speaker configured forsound conduction not using human body vibration sound but using airconduction sound. With the above configuration, even when the userforcefully presses the panel 10 against a user's body with force greaterthan or equal to 3 N or so (e.g. force ranging from 5 N to 10 N), thevibration of the panel 10 occurs. As a result, human body vibrationsound which is transmitted through a part of the user's body isgenerated. Note that a level of the voltage to be applied isappropriately adjustable according to how tightly the panel 10 is fixedto the housing or a support member or according to a capability of thepiezoelectric element 30. When the control unit 50 applies an electricsignal to the piezoelectric element 30, the piezoelectric element 30undergoes expansion and contraction or flexture in a longitudinaldirection. At this point, the panel 10 attached with the piezoelectricelement 30 is deformed in conjunction with expansion and contraction orflexture of the piezoelectric element 30, thus resulting in thevibration of the panel 10. The panel 10 undergoes flexure in response toexpansion and contraction or flexture of the piezoelectric element 30.The panel 10 is bent directly by the piezoelectric element 30. The statein which the “panel 10 is bent directly by the piezoelectric element”differs from a phenomenon in which the panel is deformed when a certainarea of the panel is vibrated due to inertial force of a piezoelectricactuator including the piezoelectric element provided in a casing asadopted in an existing panel speaker. The state in which the “panel 10is bent directly by the piezoelectric element” includes a state in whichthe panel is bent directly by expansion and contraction or bending(flexure) of the piezoelectric element via the joining member or via thejoining member and a reinforcing member 80 which is later described.Thus, the panel 10 generates air conduction sound, and the panel 10 alsogenerates human body vibration sound that is transmitted through a partof the body when the user places the part of the body (e.g. thecartilaginous portion of the external ear) in contact with the panel 10.For example, the control unit 50 may apply an electric signalcorresponding to a sound signal representing voice of the party on thephone or the like, so as to generate air conduction sound and human bodyvibration sound that correspond to the sound signal. The sound signalmay represent a phone melody, music including a tune, or the like. Thesound signal according to the electric signal may be based on music datastored in an internal memory of the electronic device 1 or may bereproduced according to music data stored in an external server and thelike via the network.

The vibration is caused in an area of the panel 10 where thepiezoelectric element 30 is disposed and in other areas of the panel 10that are away from the area where the piezoelectric element 30 isdisposed. The panel 10 includes, in the areas vibrated, a plurality ofportions that are configured to vibrate in a direction intersecting witha main surface of the panel 10, and in each of the plurality ofportions, a value indicating an amplitude of the vibration transitionsover time from plus to minus or vice versa. The panel 10 is vibratedsuch that areas with relatively large amplitude of vibration and areaswith relatively small amplitude of vibration are seemingly distributedrandomly across the panel 10 at a certain moment. In other words, thevibration of a plurality of wavelengths is detected across substantiallyall areas of the panel 10. In order to prevent the aforementionedvibration of the panel 10 from being attenuated even when the userforcefully presses the panel 10 against the user's body with forceranging from 5 N to 10 N, for example, the voltage that the control unit50 applies to the piezoelectric element 30 may be ±15 V. The aboveconfiguration allows the user to listen to sound while placing the earin contact with the areas of the panel 10 that are away from the areawhere the piezoelectric element 30 is disposed.

It is to be noted that the panel 10 may be as large as the user's ear.As illustrated in FIG. 2, the panel 10 may also be larger than theuser's ear. In this case, when the user listens to sound, the whole eartends to be covered by the panel 10 of the electronic device 1. As aresult, ambient sound (noise) is prevented from entering through theexternal auditory canal. It is suffice for the vibration to occur in anarea of the panel 10 that is larger than an area having a lengthcorresponding to a distance from an inferior crus of antihelix (i.e. aninferior crus anthelicis) to an antitragus and a width corresponding toa distance from a tragus to an antihelix. It is preferable for thevibration to occur in an area of the panel 10 that is larger than anarea having a length corresponding to a distance from a portion of ahelix that is near a superior crus of antihelix (i.e. a superior crusanthelicis) to an auricular lobule and a width corresponding to adistance from the tragus to a portion of the helix that is near theantihelix. The areas having the above lengths and widths may have arectangular shape or an elliptical shape with a major axis correspondingto the length and a minor axis corresponding to the width. Average earsize of the Japanese can be seen from the Japanese Body DimensionDatabase (1992-1994) or the like distributed by the Research Instituteof Human Engineering for Quality Life (HQL). The panel 10 with a sizegreater than or equal to the average ear size of the Japanese would begenerally capable of covering a whole ear of a foreigner as well.

The above electronic device 1 is capable of transmitting, to the user,air conduction sound and human body vibration sound which is transmittedthrough a part of the user's body (e.g. the cartilaginous portion of theexternal ear). Accordingly, when the panel 10 outputs sound atsubstantially the same volume level as a dynamic receiver, less volumeof sound propagates to an external environment of the electronic device1 due to the vibration of air resulting from the vibration of the panel10, compared to a case of the dynamic receiver. Accordingly, theelectronic device 1 is preferable for a situation where a recordedmessage is listened to on the train and the like, for example.

Furthermore, since the above electronic device 1 transmits human bodyvibration sound by the vibration of the panel 10, even when the userwears an earphone or a headphone, the user is able to listen to soundthough the earphone or the headphone and a portion of the body byplacing the electronic device 1 in contact with the earphone and theheadphone.

The above electronic device 1 transmits sound to the user by thevibration of the panel 10. Accordingly, in a case where the electronicdevice 1 is not provided with an additional dynamic receiver, it is notnecessary to provide the housing with an opening (i.e. a sound dischargeopening) for sound transmission. As a result, a waterproof structure ofthe electronic device 1 is simplified. When the electronic device 1 isprovided with a dynamic receiver, the sound discharge opening may beclosed by a member that passes air through and blocks liquid. The memberthat passes air through and blocks liquid may be Gore-Tex™, for example.

First Embodiment

FIGS. 3A and 3B illustrate the housing structure of the electronicdevice 1 according to a first embodiment. FIG. 3A is a front view, andFIG. 3B is a sectional view taken along a line b-b of FIG. 3A. Theelectronic device 1 illustrated in FIGS. 3A and 3B is a smartphone inwhich the touch panel, i.e., a glass plate, is disposed as the panel 10on a front surface of a housing 60 (e.g. a metal or a resin casing). Thepanel 10 and the input unit 40 are supported by the housing 60, and thedisplay unit 20 and the piezoelectric element 30 are each adhered to thepanel 10 by a joining member 70. Note that the joining member 70 may bethe adhesive agent, the double-sided adhesive tape, or the like havingthermosetting properties, ultraviolet-curable properties, or the like.For example, the joining member 70 may be an optical elastic resin,which is a colorless and transparent ultraviolet-curable acrylicadhesive agent. The panel 10, the display unit 20, and the piezoelectricelement 30 each have a substantially rectangular shape.

The display unit 20 is disposed in substantially a middle of the panel10 in a short-side direction thereof. The piezoelectric element 30 isdisposed near an end of the panel 10 in the longitudinal direction ofthe panel 10 at a predetermined distance from the end such that thelongitudinal direction of the piezoelectric element 30 extends along ashort side of the panel 10. The display unit 20 and the piezoelectricelement 30 are disposed side by side in a direction parallel to asurface of an inner side of the panel 10.

FIG. 4 illustrates one example of the vibration of the panel 10 of theelectronic device 1 according to the first embodiment. In the electronicdevice 1 according to the first embodiment, the display unit 20 isattached to the panel 10. Accordingly, the lower portion of the panel 10is less likely to vibrate compared to the upper portion of the panel 10attached with the piezoelectric element 30. As a result, in the lowerportion of the panel 10, sound leakage due to the vibration occurring inthe lower portion of the panel 10 is reduced. The panel 10 in the upperportion thereof is bent directly by the piezoelectric element 30, andthe vibration in the lower portion is attenuated compared to thevibration in the upper portion. The panel 10 is bent by thepiezoelectric element 30 such that a portion of the panel 10 directlyabove the piezoelectric element 30 protrudes relative to neighboringportions of the panel 10 in a long-side direction of the piezoelectricelement 30.

As described above, according to the electronic device 1 of the presentembodiment, the panel 10 is deformed due to deformation of thepiezoelectric element 30 attached to the back surface of the panel 10,and air conduction sound and human body vibration sound are transmittedto an object that is in contact with the deformed panel 10. As a result,air conduction sound and human body vibration sound are transmitted tothe user without having to protrude the vibration body from an outersurface of the housing 60. Accordingly, usability of the electronicdevice is improved compared to such an electronic device as described inPatent Literature 1 (Japanese Patent Application Publication No.2005-348193), by which the user places the vibration body, which issignificantly small compared to the housing, in contact with the body.Furthermore, since there is no need for pressing the user's ear to thepiezoelectric element itself, the piezoelectric element 30 itself isless likely to be damaged. Moreover, although in a case where not thepanel 10 but the housing 60 is deformed the user tends to drop aterminal device while the vibration is generated, such dropping is lesslikely to occur in the case where the panel 10 is vibrated.

The piezoelectric element 30 is joined to the panel 10 by the joiningmember 70. The above structure allows attachment of the piezoelectricelement 30 to the panel 10 in a manner such that flexibility ofdeformation of the piezoelectric element 30 is less likely to belimited. The joining member 70 may be a non-thermosetting adhesiveagent. The above structure provides an advantage that contraction due toa thermal stress is less likely to occur during curing between thepiezoelectric element 30 and the panel 10. The joining member 70 may bethe double-sided adhesive tape. The above structure provides anadvantage that a contraction stress, which often occurs when theadhesive agent is used, is less likely to be applied between thepiezoelectric element 30 and the panel 10.

Second Embodiment

FIGS. 5A-5C illustrate the housing structure of the electronic device 1according to a second embodiment. FIG. 5A is a front view, FIG. 5B is asectional view taken along a line b-b of FIG. 5A, and FIG. 5C is asectional view taken along a line c-c of FIG. 5A. The electronic device1 illustrated in FIGS. 5A-5C is a foldable mobile phone in which a coverpanel (e.g. an acryl plate), which serves as the panel 10 and configuredto cover the display unit 20, is provided on a front surface of anupper-side housing 60. In the second embodiment, the reinforcing member80 is disposed between the panel 10 and the piezoelectric element 30.The reinforcing member 80 may be a resin plate, a metal plate, or aresin plate including glass fiber. That is to say, the electronic device1 according to the second embodiment has a structure where thepiezoelectric element 30 and the reinforcing member 80 are adhered bythe joining member 70, and the reinforcing member 80 and the panel 10are adhered by the joining member 70. Furthermore, in the secondembodiment, the display unit 20 is not adhered to the panel 10 butsupported by the housing 60. That is to say, the electronic device 1according to the second embodiment has a structure where the displayunit 20 is spaced apart from the panel 10, and the display unit 20 isadhered to the support portion 90, i.e., a part of the housing 60, bythe joining member 70. The support unit 90 is not limited to beconfigured as the part of the housing 60 and may be configured by metal,resin, or the like, as a member independent from the housing 60.

FIG. 6 illustrates one example of the vibration of the panel 10 of theelectronic device 1 according to the second embodiment. Since in theelectronic device 1 according to the second embodiment the panel 10 isthe acryl plate with lower rigidity compared to the glass plate, andmoreover, the display unit 20 is not adhered to the back surface of thepanel 10, amplitude generated by the piezoelectric element 30 is largerthan the case of the electronic device 1 according to the firstembodiment as illustrated in FIG. 4. The vibration is generated in anarea of the panel 10 where the piezoelectric element 30 is disposed andin areas of the panel 10 that are away from the disposed area.Accordingly, the user is able to hear air conduction sound transmittedthrough air and to hear human body vibration sound by placing the ear incontact with any position of the panel 10.

As described above, according to the electronic device 1 of the presentembodiment, the reinforcing member 80 and the panel 10 are deformed dueto deformation of the piezoelectric element 30 attached to the panel 10via the reinforcing member 80, and air conduction sound and human bodyvibration sound are transmitted to an object that is in contact with thedeformed panel 10. Accordingly, air conduction sound and human bodyvibration sound are transmitted to the user without the need forpressing the vibration body itself to the ear. Furthermore, thepiezoelectric element 30 is attached to the surface of the panel 10 onthe inner side of the housing 60. Accordingly, air conduction sound andhuman body vibration sound are transmitted to the user without having toprotrude the vibration body from the outer surface of the housing 60.Moreover, the deformation occurs in the area of the panel 10 where thepiezoelectric element 30 is disposed and in other areas of the panel 10,for transmission of air conduction sound and human body vibration sound.Accordingly, the user is able to hear air conduction sound transmittedthrough air and to hear human body vibration sound by placing the ear incontact with any position of the panel 10.

Furthermore, by disposing the reinforcing member 80 between thepiezoelectric element 30 and the panel 10, when the panel 10 is appliedwith an external force, the applied external force is less likely to betransferred to the piezoelectric element 30 and damage the piezoelectricelement 30. Even when the panel 10 is forcefully pressed against thehuman body, the attenuation in the vibration of the panel 10 is reduced.Moreover, owing to the reinforcing member 80 disposed between thepiezoelectric element 30 and the panel 10, a resonance frequency of thepanel 10 is lowered, and an acoustic characteristic in a low frequencyband is improved. Note that instead of the reinforcing member 80 aplate-shaped weight may be attached to the piezoelectric element 30 bythe joining member 70.

Although the present invention has been described based on the drawingsand the embodiments thereof, it should be noted that a person skilled inthe art may easily make a variety of modifications and alterationsaccording to the present disclosure. Note that the modifications andalterations are within the scope of the present invention. For example,functions and the like included in the components and steps may berearranged as long as the functions and the like are logicallyconsistent. A plurality of component parts, the steps, and the like mayalso be integrated or separated.

For example, as illustrated in FIG. 7, the panel 10 may be configured tobe joined to the housing 60 by the joining member 70. By thus preventingthe vibration of the panel 10 from being transmitted directly to thehousing 60, the risk that the user drops the electronic device 1 isreduced compared to the case where the housing itself undergoes a largevibration. The joining member 70 may be the non-thermosetting adhesiveagent. The above structure provides an advantage that contraction due toa thermal stress is less likely to occur during curing between thehousing 60 and the panel 10. The joining member 70 may be thedouble-sided adhesive tape. The above structure provides an advantagethat a contraction stress, which often occurs when the adhesive agent isused, is less likely to be generated between the housing 60 and thepanel 10.

When the panel 10 and the display unit 20 are not superposed, forexample, the piezoelectric element 30 may be disposed in the middle ofthe panel 10. When the piezoelectric element 30 is disposed in themiddle of the panel 10, the vibration of the piezoelectric element 30 isevenly transmitted to the whole panel 10, thereby improving a quality ofair conduction sound and allowing the user to perceive human bodyvibration sound even when the user places the ear in contact with thepanel 10 at different positions of the panel 10. Note that, similarly tothe first embodiment, the piezoelectric element 30 may be provided inplurality.

Although in the above electronic device 1 the piezoelectric element 30is adhered to the panel 10, the piezoelectric element 30 may be attachedto another place than the panel 10. For example, the piezoelectricelement 30 may be adhered to a battery lid that is configured to beattached to the housing 60 to cover a battery. Since the battery lid isoften attached to a surface different from the panel 10 in theelectronic device 1 such as the mobile phone, the above structureenables the user to listen to sound by placing a portion of the body(e.g. the ear) in contact with the surface different from the panel 10.

The panel 10 may form a part or an entirety of any of a display panel,an operation panel, the cover panel, and a lid panel that allows arechargeable battery to be detachable. Preferably, when the panel 10 isthe display panel, the piezoelectric element 30 is disposed outside of adisplay area provided for a display function. The above structureprovides an advantage that display is less likely to be disturbed. Theoperation panel includes the touch panel of the first embodiment. Theoperation panel may also include a sheet key, namely, a component of thefoldable mobile phone or the like that is integrally provided with a keytop as the operation key and that forms one surface of the housing on anoperational side.

Meanwhile, in the first embodiment and the second embodiment, thejoining member used for adhering the panel 10 and the piezoelectricelement 30, the joining member used for adhering the panel 10 and thehousing 60, and the like are denoted by the same reference numeral asthe joining member 70. However, the joining members used in the firstembodiment and the second embodiment may be different depending on thecomponents to be joined, as appropriate.

REFERENCE SIGNS

-   -   1 electronic device    -   10 panel    -   20 display unit    -   30 piezoelectric element    -   40 input unit    -   50 control unit    -   60 housing    -   70 joining member    -   80 reinforcing member    -   90 support portion

The invention claimed is:
 1. An electronic device, comprising: a panel;a housing configured to support the panel; and a unimorph piezoelectricelement attached to the panel, wherein sound is transmitted by bendingthe panel with the unimorph piezoelectric element such that a portion ofthe panel directly above the unimorph piezoelectric element protrudesrelative to neighboring portions of the panel in a long side directionof the unimorph piezoelectric element and by vibrating a contacting partof a human body that is in contact with the bent panel, and a vibrationoccurs in an area of the panel that is larger than an area having alength corresponding to a distance from an inferior crus of antihelix toan antitragus and a width corresponding to a distance from a tragus toan antihelix of an ear of a human being.
 2. The electronic device ofclaim 1, wherein the unimorph piezoelectric element is attached to asurface of the panel on an inner side of the housing.
 3. The electronicdevice of claim 1, wherein the unimorph piezoelectric element is joinedto the panel by a first joining member.
 4. The electronic device ofclaim 3, wherein the first joining member comprises a non-thermosettingadhesive agent.
 5. The electronic device of claim 3, wherein the firstjoining member comprises a double-sided adhesive tape.
 6. The electronicdevice of claim 1, wherein the panel is joined to the housing by asecond joining member.
 7. The electronic device of claim 6, wherein thesecond joining member comprises a non-thermosetting adhesive agent. 8.The electronic device of claim 6, wherein the second joining membercomprises a double-sided adhesive tape.
 9. The electronic device ofclaim 1, wherein the panel forms a part or an entirety of any of adisplay panel, an operation panel, a cover panel, and a lid panel thatallows a rechargeable battery to be detachable.
 10. The electronicdevice of claim 9, wherein the panel comprises the display panel, andthe unimorph piezoelectric element is disposed outside of a display areaprovided for a display function.
 11. The electronic device of claim 1,wherein deformation, which causes the transmission of air conductionsound and human body vibration sound, occurs in any areas of the panel.12. The electronic device of claim 1, wherein the panel includes, inareas thereof that are vibrated, a plurality of portions that areconfigured to be vibrated in a direction intersecting with a surface ofthe panel, and in each of the plurality of portions, a value indicatingan amplitude of the vibration transitions over time from plus to minusor vice versa.
 13. The electronic device of claim 1, wherein the panelis larger than an ear.
 14. The electronic device of claim 1, wherein theelectronic device is a smartphone or a foldable mobile phone.
 15. Anelectronic device, comprising: a unimorph piezoelectric element; a panelto which the unimorph piezoelectric element is joined for vibration; anda housing to which the panel is joined, wherein sound is transmitted bybending the panel with the unimorph piezoelectric element such that aportion of the panel directly above the unimorph piezoelectric elementprotrudes relative to neighboring portions of the panel in a long sidedirection of the unimorph piezoelectric element and by vibrating apressed part of a human body that is pressed against the bent panel, anda vibration occurs in an area of the panel that is larger than an areahaving a length corresponding to a distance from an inferior crus ofantihelix to an antitragus and a width corresponding to a distance froma tragus to an antihelix of an ear of a human being.
 16. The electronicdevice of claim 15, wherein, when pressed with force greater than orequal to 3 N, the pressed part is vibrated, and sound is transmitted.17. The electronic device of claim 15, wherein, when pressed with forcegreater than or equal to 5 N, the pressed part is vibrated, and sound istransmitted.
 18. The electronic device of claim 15, wherein, whenpressed with force less than or equal to 10 N, the pressed part isvibrated, and sound is transmitted.